AD7142ACPZ-REEL

数据采集ADC/DAC – 专业 Capacitance tp Digital Converter

Product Details

The AD7142 and AD7142-1 are integrated capacitance-to-digital converters CDCs with on-chip environmental calibration for use in systems requiring a novel user input method. The AD7142 and AD7142-1 can interface to external capacitance sensors implementing functions such as capacitive buttons, scroll bars, or wheels.

The CDC has 14 inputs channeled through a switch matrix to a 16-bit, 250 kHz sigma-delta ∑-Δ capacitance-to-digital converter. The CDC is capable of sensing changes in the capacitance of the external sensors and uses this information to register a sensor activation. The external sensors can be arranged as a series of buttons, as a scroll bar or wheel, or as a combination of sensor types. By programming the registers, the user has full control over the CDC setup. High resolution sensors require minor software to run on the host processor.

The AD7142 and AD7142-1 have on-chip calibration logic to account for changes in the ambient environment. The calibration sequence is performed automatically and at continuous intervals, when the sensors are not touched. This ensures that there are no false or nonregistering touches on the external sensors due to a changing environment.

The AD7142 has an SPI-compatible serial interface, and the AD7142-1 has an I2C-compatible serial interface. Both parts have an interrupt output, as well as a general-purpose input/ output GPIO.

The AD7142 and AD7142-1 are available in a 32-lead, 5 mm × 5 mm LFCSP_VQ and operate from a 2.6 V to 3.6 V supply. The operating current consumption is less than 1 mA, falling to 50 μA in low power mode conversion interval of 400 ms.

**Applications**

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Personal music and multimedia players

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Cell phones

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Digital still cameras

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Smart hand-held devices

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Television, A/V, and remote controls

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Gaming consoles

### Features and Benefits

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Programmable capacitance-to-digital converter

36 ms update rate @ maximum sequence length

Better than 1 fF resolution

14 capacitance sensor input channels

No external RC tuning components required

Automatic conversion sequencer

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On-chip automatic calibration logic

Automatic compensation for environmental changes

Automatic adaptive threshold and sensitivity levels

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On-chip RAM to store calibration data

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SPI®-compatible serial interface AD7142

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I2C®-compatible serial interface AD7142-1

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Separate VDRIVE level for serial interface

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Interrupt output and GPIO

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32-lead, 5 mm x 5 mm LFCSP_VQ

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2.6 V to 3.6 V supply voltage

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Low operating current

Full power mode: less than 1 mA

Low power mode: 50 μA

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